The Personality number is taken from the consonants of the birth name, and the system reads it as the outer surface: what other people meet first, the manner rather than the motive. The Minor Personality applies that same rule to the name the person actually uses. The consonants of the working name are summed, the vowels are ignored, and the total is reduced to a single figure, with the master numbers kept.
The division of a name into vowels and consonants is the structural move on which three positions in this chart depend. Vowels are held to carry what is interior and unspoken, consonants what is presented. Soul Urge takes the vowels, Personality takes the consonants, and Expression takes both together, so that the two halves are supposed to add up to the whole in meaning as well as in arithmetic.
Applied to the working name, the position is used to describe the impression a person makes in the setting where that name is current. A performer with a stage name and a very different legal name is the textbook case: the Minor Personality is offered as an account of the persona, and the Personality of the person the persona is built over. Practitioners read the two together and treat a wide gap between them as the interesting result rather than an error.